Native erythrocytes and those treated by many prior art procedures useful for indirect hemagglutination testing such as blood typing suffer from the disadvantage that they deteriorate rapidly on storage so that for typing purposes they are considered useless after about 21 days and are required to be replaced. Examples of methods directed at stabilization of red blood cells include U.S. Pat. No. 3,714,345, to Hirata which describes an erythrocyte preparation wherein stabilization is accomplished by sequential exposure of the blood cells to dilute solutions of pyruvic aldehyde and formaldehyde. See also U.S. Pat. No. 3,715,427, also to Hirata. Literature of interest includes the following references: Ling, Brit. J. Haemat., Vol. 7, 1961 (pp. 229 - 302); Kabat, Exptl. Immunochem. CC Thomas, Springfield, Ill., 2nd Ed., 1961 (pp. 542 - 550); Chem. Abs., Vol. 55 (1961) pp. 27495; Vol. 65 (1966) pp. 20497, 20672; and, Ingraham, PSEBM Vol. 99, Nov., 1958 (pp. 452 - 456).